Fluorescent tube



Jan. 22, 1946.

w. c.- GREF FLUORESCENT TUBE OriginaLFiied Aug. 22, '1940 v INVENTOR WaZZzam BY 5 Grej" Reissues! 10.11.22, 1946 v R Re. 22,712

UNITED STATES PATENT orrics FLUORESCENT TUBE William O. Gref, Westport, Conn, assignor, by

mesne assignments, to TheWheeier Insulated' Wire Company,- Incorporated, Bridgeport, Conm, a cor mratiarnnoi Delaware Original No. 2,293,897, dated August 25 1942,

Serial No. 353,611, August 22, 1940. Application for reissue March 25, 1943, Serial- No.

13 Claims. (Cl. sis-o) The present invention relates to fluorescent tube circuits, and, more particularly, to the combination in which a resettable automatically ope'rable switch is included in the starter means for the circuit.

In fluorescent tube circuits, the filaments of the tube are connected through a starter switch heat-responsive switch having one of the contacts normally urged into open-circuit position, but held in closed-circuit position by a. heatresponsive detail: or the like. The movable member of the switch is provided with a button or manual operator which is normally disposed within the housing, but, upon operation of the switch to open the circuit, projects beyond the housing. This not only provides a manual actuator for resettin .theswitch, but also an indicator for signalling that the circuit has been opened at the starter switch.

Should there be difficulty in the circuit, such as the tubes becoming deactivated and the automatic switch in the starter open, the user of the device will be immediately apprised of this fact and can remedy the situation. on the other in the lighting circuit because of the abnormal load. I Also, if one of the filaments of the tube becomes shorted, a high current will flow through the starting means and also will place a load on the circuit.

To avoid these conditions, efforts have been made to provide a protecting means on the starter means by including a soft metal fuse within the starter can 'which melts upon an abnormal current flow in thecircuit or a normal current flow of abnormal duration.

' This method has not been, entirely satisfactory, for the starter switches and fuse have been enclosed in a can or housing. When the fuse wasdestroyed, the entire starting unit, which, under I normal conditions, would operate for many hours, had to be discarded. Thus, the life of the startin the circuit, the present invention provides, in

the starter, an automatic switch means which will open the circuit after a predetermined interval should the current be excessive or should the normal currentpass through the switch for an abnormal time.

This is accomplished by replacing the fuse in thestarter unit with an automatically operable switch which may be reset after it has been caused to operate to open the circuit.

Whilethe switch may take many forms, in the preferred form of. the invention it comprises awith the starter means but hand, should the lights fail to operate and the automatic switch remain closed, the user of the .20.

device willknow at once that the diflicuity is not with some other portion of the circuit.

, After the switch has opened the circuit and the user has corrected the trouble, the switch can be again closed and the heating circuit established. In the event that the trouble has not been entirely corrected, the switch will again operate to open thew circuit. and the trouble can be traced further. It will be apparent from this operation that a great saving in starting units will be had and a greater efficienc in the lighting circuit obtained.

' Other features and,advantages of the invention will be apparent from the specification and claims when considered in connection withthe drawing, in which:

Figurel shows a diagrammatic view of a fiuorescent tube circuit showing two tubes with starter means therefor partly in section.

, Fig. 2 is a sectional view of the starter unit, taken along lines 2-2 of Fig. 1.

Fig, 3 is a sectional view, similar to Fig, 2,- showin'g. a modified form of the invention.

In'the drawing, two fluorescent-tubes Ill and Ii are shown. Itis to be understood that the present invention is applicable .to circuits of one or more tubes and that the present illustration is used to facilitate description of the invention.

The fluorescent tube II is provided with filaments Ilia, Ilib which are located in each. end thereof and are connected together through a starter circuit, including an automatic can starter its to form a heating circuit therefor. The filaments are also connected to a suitable source of power indicated at It. The source of power I 22,712 may be an autotransformer as illustrated in the drawing, or a choke coil connected across the 7.

power line l2,

The fluorescent tube I l similarly has filaments I la. and lib located at either end .thereof and the filaments are into a heating circuit,

including. anautomatic starter lie. The fllaments are across the power supply The starter units,..which are shown section;

aresimilar. ahd'comprise a can or-housing i5 havcircuit.

or cause the-normal current abnormal time. If the fluorescent tube the user wouldhave an indication that there was an open line or other troubleelsewhere' in the In some installations it is impractical to have the reset button to project from the end of. the

housing can. as shown in Fig.1, because of space 7 requirements. In such instances, the switch of ing terminals in, ru the bottom thereof for connection intoth'e'heating circuit. Terminal I6 is connected to, one element of the starter switch I I which is enclosed in'a'glass tube- I 9. The other element oitheswitch-JB is connected to one conand serves as a'means tact oi theresettable switch of the present invention, and the other contact of the resettabie switch is connected to theterminal ll.

In the illustrated form" of the invention, the automatic operable resettable switch comprises a resilient or spring contact member 20. scured to the glafistubed. and extending across the top thereof. Positioned in spaced relation with contact 20, preferably on the opposite side of the glass tube is abimetallic arm 2| formingthe other contact of the switch. The arm has a latch or detent 22 formed at the tree end thereof, and the other end secured to the glass" tube. The two contacts may be secured in any manner to the tube, as, for example, by meansof a stripof insulating-material, cambric, or" the like.

The latched end 22 of thearm- 2| extends into the path of movement of the contact and interlocks therewith when the .contact is moved to the present inventionl'may be. arranged in .the starter can so that it projects from the side thereof, as shown in'Fig. 3. In this construction, the

spring contact 20 is positioned :so as to extend around the'tube I! and havethe'projection 24a extend throughan opening25a in the side of the housing. I

If further space limitations present themselves so that the member .24 cannot be projected through the housing, ,thenthe contact may be suitably, colored to showthrough the opening and an instrument made of insulating material provided to be inserted through the opening to reset the contact when desired.

The spring contact 20a, which is held closed by the detent 22a on the bimetallic contact arm 2 la,

is provided with a cam surface 20!: which moves the detent 22a to permit the contacts to become interlocked. As is shown in Fig. 3, the contacts are secured to the tube I! so as to extend around the side thereof.

closed position to hold the circuitclosed. The end 2212 of the detent provides a cam surface for shifting the arm as the contact 20 is moved into position. The bimetallic contact with" its detent .will n'ormalLv hold the circuit closed. when the bimetallic arm is'h eated upon an abnormal con dition, however, it will flex and releasethe contact" which springs to open position.

, While in the two forms of .the invention illustrated the switch contacts have been mounted on the tube It, they may, if desired, be secured to the inner surface of the can and insulated therefrom f or be otherwise mounted in the can.

. In the broader aspects of the invention, .there is provided within the housing of the automaticstarter means an'automatically operated resetta-,

' ble switch which will be operated topermanently The'bimetallicarm II-ma'y beof such cross-f section that the normal current passing therethrough willnot heat it sumciently tocause it to flex during the operation of -the switch ll, but which will cause the same to be heated byabnorma] current passing therethrough and cause it'to A flexto release the contact 2|. a r If desired, the bimetallic.arm, can be to flex the bimetallic memberl2i.

'As is shown In.F ig.'1, thecontact 201s with'a projecting member IFwhich-is disposed I adiacent'an openin ll in the hq fllnswh n thefswitch is :in closed, position, the member 2|,

open the circuit upon an abnormal condition therein after a predetermined time interval,

which'switch can be manually reset upon correc-. tion of the condition producing the abnormal condition. I

Variations and modifications may be made within the scope of this invention and portions of provided -with a heating member 23, as shown in'Fig. -1',- h which is connectedto the 'e'lementcf the switch; .tl sothat the curre'nt in-the heating circuitwi'll pass therethrough and'provide' the heat necessary the improvements may be used'without others.

I-claim:

' 1. .In-a fluorescent tube circuit, a fluorescent :tube: protectedstarter means in-the filament circuit of the tub'e for automatically temporarily I closing said. circuit toheat the fllamentsyand '55.

the tube to become conductive and. to repeat-said operation until said tube becomes conductive; and meansforsupplying a proper voltage to .the tube to maintain the tube conduclies substantiall'yfjwithin the housing." However,'-:"

starter in 1 r so t projects substantially .Ths proiecting portionalso sci-veins and; cater of the condition of. the switch so that the user. of the device canreadily perceive that'the upon the switch operated to open heatingfcircuit,the-member moves irom the g no showninj'the rower of rig.- -1 to the. position shown dotted lines in the upper beyond the the 1 m .V r by the switch can j e'manualiy m v circuit has been opened in the starterfunit and. remedy the situation which would cause the current the starter circuit to be abnormally large tive, said protected starter means comprising a "housing enclosing an automatic electron I switch and a heat-responsive switch carried by the electric switchadapt d to'open. the circuiti upon being heated by abnormal current'flow 'therethrough and by heat caused by abnormal repeated operations of said switch and .trans--' ierred'irom said electron switch, said heat raswitch beinsnormmr ursed lto' opencircuit-ilpositmn .and having means thereon to project from the housing when the 'switch' isin open-circuit position to indicate the conditioner the starter means and form. a meam for resetting the heat-responsive switch. a

2.- In a fluorescent tube. circuit, a fluorescent tube; protected starter means in the filament circuit of the tube for automatically temporarq to remain for an r I should fail to operate and the circuit remain closed in the starter, then -ing a proper voltage to the tube to maintain the tube conductive, said starter means having an automatic starter switch sealed in a tube ,of insulating material, a spring contact carried by the tube, and a bimetallic latch contactcarried by the tube in spaced relation with the spring contact and cooperating therewith to hold the.

circuit closed, the contacts being in series with the starter switch and the spring contact being normally urged to open-circuit position, saidbimetallic latch contact being heated by heat caused by repeated operations of the switch and transferred from the tube and by an abnormal current condition in the circuit and releasing the spring contact for movement into open-circuit position, and means carried by .the spring "contact for manually returning the spring contact to closed-circuit position. I

3. Ir: a fluorescent tube circuit, a fiuorescen tube; protected starter means in the filament circuit of the tube for automatically temporarily closing said circuit to heat the filaments and cause the tube to become conductive and'to repeat said operation until said tube becomes conductive;'means for supplying a proper voltage to the tube to maintain the tube conductive, said starter means having a. housing enclosing an electron switch sealed in a tube of insulating 'material, a spring contact carried by the tube, and a bimetallic latch contact carried by the tube in spaced relation to the spring con- .tact and cooperating with the spring contact to hold the circuit closed; the contacts being disposed within the housing and connected in series with the starter switch with the spring contact connected in series with the starter means and carried by the starter means said switch being operated to permanently open the circuit upon repeated operationsot the starter meansor an: abnormal condition in said starter means: and

means controlled by theresettable switch for indicating the position of said switch in the heating circuit.

6. A protectedstarter unit to be used in the filament circuit oi a fluorescent tube, comprising a housing; an automatic switch means, surrounded by the housing, to be connected in the filament circuit of the tube and operable for closing a heating circuit to the filaments; and separate control meansin said circuit, said means being carried by the automatic switch means and enclosed by said housing and being responsive to abnormal current. in the heating circuit for opening the circuit comprising a switch urged to opencircuit position, a heat-responsive member for normally maintaining said switch closed and for releasing the switch .upon passage of an abnormal current in the'fllament circuit, and a manual operator carried by the movable switch part and moved to the exterior of the housing when the switch is in open-circuit position whereby the being normally urged to open-circuit position,

said bimetallic latch contact being heated by heat from the electron switch tube and by an abnormal current condition in the circuit and flexing to release the spring contact for movement into open-circuit position; and means car-- ried by the spring contact and projecting beyond the housing when the switch is in open-circuit position for indicating the conditioner the circult and providing a manual actuator for returning the spring contact in cooperative relation with the latch contact to close the circuit.

4. A protected starter unit to be used in the filament circuit of a fluorescent tube comprising a housing, .an automatic starter switch means enclosed therein to be connected in the filament circuit of the fluorescent tube for temporarily closing said circuit to heat the filaments and cause said tube to become conductive and to repeat said operation until said tube becomes conductive, and a resettable switch in said circuit and carried by the starter means within the housing and adapted to permanently open the circuit upon repeated operations 01' the starter means or change from a normal condition in the starter means.

5. A protected .starter unit to be used in' a fluorescent tube circuit, comprising a housing: an automatic starter means including a switch enclosed by said housing and adapted to be connected in the filament circuit of the tube for temporarily closing a heating circuit for the filaments for a period sufficient to heat the filaments to cause the tube to become conductive and to repeat said operation until said tube becontact cooperating with the spring contact to switch can be engaged and again moved into closed-circuit position.

7. A protected automatic starter unit to be inserted in the filament circuit of a fluorescent tube,

comprising a housing having terminals thereon across said terminals for temporarily closing said circuit to cause the fluorescent tube to become conductive andrepeating the circuit-closing operation until said tube does become conductive, a

'spring contact, and a bimetallic latch contact carried by the tube, in spaced relation with one another and connected in series with the switch circuit, the spring contact being normally urged to open-circuit'posltion and the bimetallic latch hold the circuit closed, said bimetallic latch contact being heated upon an abnormal current condition in the circuit and by heat, caused by repeated operations of said automatic starter switch or an abnormal condition in said starter switch, transferred from the tube surrounding 8. A fluorescent lamp; a starting circuit in parallel with said lamp; a starting switch in said 7 starting circuit for starting the lamp in operation, said switch operating when the lamp is out and starting voltage is applied thereto to efi'ect repeated opening and closing of said starting circuit until the lamp lights; a choke coil in series with said lamp operable each time the starting circuit is broken to induce a relatively high voltage across said lamp for lighting the lamp; and a protective switch connected in series with said starting switch in said starting circuit. said protective switch being biased to open position and 7 having means for latching it in closed position and comes conductive; a separate resettabie switchto-eilect the opening otsaidprotective switch to break said startingcircuitin the event the conswitch bimetallic strip operable to cause the bendtinue'd operation oi starting switch tails to 1 -1start said lamp; in within a. predetermined time interval ltheinitial operationof 1 said starting switch;

9. A, fluorescent. lamp'havi'ng heater in the ends thereof; a choke coil-in series-with said lamp; a starting circuit in parallel with said lamp; a'starting switch having contactsin ,said

saris of tension', said ends Oflhld' protective switch bimetallic strip and contact spring serving as contacts, and heating means (or said protective 1118 of said protective switch bimetanic strip under the continued operation oi said starting switch starting circuit, andmeans operable upon the connection of the lamp to'itssou'rce to cause the engagement oi said' contacts to complete said starting circuit and thereupon acting to eilect'the separationoi said contacts to break said starting circuit, said choke 'coil acting upon the breaking of said starting circuit to induce a relatively high voltage across said lamp electrodes to light said lamp, said means causing the repeated engagement and separation of said contacts in the event said lamp fails to light but causing them to remain separated after the lamp lights; and a protective switch connected in series with said starting switch in said starting circuit, said protective switch comprising a pair of contacts, meansbiasing said protective switch contacts to disengaged condition, a latch for holding said protective switch contacts in engagement against the force said biasing means, and means controlledby the flow of current in said starting circuit for releasing said latch to effect the separation of said protective switch contacts and thus break said starting circuit in the event the continued operation of said starting switch tails to'start said lamp in operation within a predetermined time interval after connection of said lamp to said source.

10. A fluorescent lamp having heater electrodes in the ends thereof: a chock coil in series with said lamp; a starting circuit in parallel with said lamp; a starting switch in said starting circuit, said starting switch having a stationary contact and a movable contact, and means operable upon the connection oi the lamp to-its source to cause the engagement 01 said contacts to complete the starting circuit connecting said lamp electrodes in series to said source, said means acting to effect the disengagement of said contacts aite'r the completion of the starting circuit to break said circuit,

fails to start said lamp inoperation within a predetermined time interval after connection of said lamptosaid source,

11. In a-fluorescent lamp circuit, a fluorescent lamp, an inductance in series with said lamp: starting switch means in the starter circuit for .the lamp for temporarily closing the lamp circuit 7 starting of the lamp and movable to permanently open the circuit only upon excess operation oi said starting switch; and means for resetting the protective switch means to closed-circuit position in response to a manual operation.

12. In a fluorescent lamp circuit, a fluorescent lamp. an inductance in series with said lamp; starting switch means in the starter circuit for the lamp for temporarily closing the lamp circuit I, tocause said lamp tobecome operative, the operation 01' said starting switch means being repeated until said lamp becomes operative; bimetallic switch means in the starter circuit and connected in series with said starting switch and movable to permanently open the circuit only upon excess operation 01' said starting switch; and means for resetting the bimetallic switch to closed-circuit position in response to a manual operation.

13. A fluorescent lamp; a starting circuit in parallel with said lamp; a switch in said starting circuit for starting the lamp-in operation, said switch operating when the lamp is out and startsaid choke coll acting upon thebreaking of said the end oi the contact spring tolatch it in a state 60 ing voltage is applied thereto to effect repeated opening and closing of said starting circuit until the lamp lights; an inductance in series with said lamp operable'each time the starting circuit is broken to induce a relatively high voltage across said lamp for lighting the lamp; a protective switch connected in series with said starting switch in said starting circuit, 'said protective switch maintaining the starting circuit closed during normal starting and restarting of the lamp and movable to permanently open the circuit only upon excess operation of the starting switch after the initial operation of said starting switch; and manually operable means for resetting the protective switch after the'circuit has been opened thereby.

WILLIAM C. GREF. 

